1. Field of the Invention
The present invention relates to a drying machine, and more particularly, to an automatic drying machine and a method of operating the drying machine for drying a load of wet fabrics according to a set of optimal operation values determined on the basis of load information including the load size and fabric blend that are previously determined by a separate washing machine.
2. Discussion of the Related Art
On most of the currently existing washing machines (washers), the amount of water that the machines use, the velocity-toque waveforms of the agitation, and/or the tub speeds (e.g., centrifugal extraction or spin-dry speed) for a wash or dehydration cycle are often determined by load information including the load size (e.g., load weight or mass) and/or fabric type of a load of clothes, which are usually selected by the user via a manual control. However, the manual selections of such load sizes and fabric types may not provide the optimal washing option for a given load of clothes because such manual controls often offers only a limited number of selections such as small, medium, and large for the load sizes and cotton, wool, and polyester for the fabric types or because the user may unintentionally select inaccurate load information. For example, if a small load size is selected by the user for a large load of clothes, the clothes will not be washed effectively. On the other hand, if a load size, which is larger than is actually needed for the optimal washing process for a given load of clothes, is selected by the user, the use of more water than is needed for the optimal washing process will result a wasteful use of water and energy during the wash or dehydration (or spin-dry) cycle.
In order to resolve the mentioned problem, several automatic calculations of the load size and/or fabric type of a given load of fabrics to be washed have been suggested as one of the possible ways of reducing any wasteful energy and water consumption and optimizing the washing performance of the washing machine by using the automatically calculated load information for determining agitation waveform, tub speed, and the optimal amount of water added to the washer for a washing cycle. For example, one of the well known ways of determining the load size of a load of clothes is to determine the moment of inertia of the load by operating the motor with a constant torque and measuring the time required for the motor to accelerate the clothes basket and the load of clothes from a first predetermined speed to a second predetermined speed. In general, it takes more time for the motor to accelerate the load of clothes, as the load size is greater and vice versa.
However, an ordinary washing machine that uses the load information, which is automatically calculated by a controller or manually inputted by the user as described above, in determining the optimal washing option does not have an interface unit for transmitting such load information to another laundry device (e.g., dryer). Therefore, when the user desires to operate a separate drying machine for drying a load of wet clothes which are already washed and dehydrated by the washing machine, he or she must manually input the load information or the automatic calculation of the load information must be done again for optimizing the drying performance of the drying machine and for reducing any wasteful energy consumption. Consequently, this may cause great inconvenience to the user or may add great complexity to the drying machine. For these reasons, it is desirable to provide a washing machine that includes an interface unit for being connected to a separate drying machine so that the load information automatically calculated by the washing machine (or manually selected by the user) before or during a washing cycle can be transmitted to the drying machine. In addition, it is also desirable to provide a drying machine that is connected to a separate washing machine and is able to determine the optimal drying option for a given load of wet clothes based on the load information that it receives from the washing machine without the necessity of adding a complex equipment in the drying machine that makes it more complicate and unnecessarily expensive.